You don't have access to the alternate universe where they didn't introduce a loyalty program to compare prices. Grocery prices go up naturally due to inflation so it's impossible to disentangle.
Groceries are also one of the most price sensitive items people buy and grocery stores run on incredibly thin margins so it's dubious to believe that a grocery story has much control over their pricing, independant of a loyalty card. If they could raise prices after the introduction of a card to increase total profits, why couldn't they have done it before then?
Far more likely is that they're using the extra revenue from the card to lower prices for you and gain market share from their competitors but the lower prices are swallowed up by general price increases.
People who don't sign up loyalty programs and other similar schemes have shown that they aren't price sensitive. They're the ideal segment to fleece via price discrimination.
Groceries are also one of the most price sensitive items people buy and grocery stores run on incredibly thin margins so it's dubious to believe that a grocery story has much control over their pricing, independant of a loyalty card. If they could raise prices after the introduction of a card to increase total profits, why couldn't they have done it before then?
Far more likely is that they're using the extra revenue from the card to lower prices for you and gain market share from their competitors but the lower prices are swallowed up by general price increases.